MEMS Switch Triggered by Shock and/or Acceleration

An acceleration-triggered or shock-triggered, smart, tunable MEMS switch that may function as both a classic accelerometer and an acceleration threshold detector. 

Background:

Accelerometers are devices that provide an electrical signal output related to an acceleration level to which the accelerometer is subjected. Accelerometers are useful for numerous applications such as inertial navigation where continuous readings related to instantaneous acceleration are required.

 Technology Overview:  

MEMS-centric smart switch (sensor + switch) applicable to low-power, highly sensitive detection of perturbations of an oscillating or vibrating structure.  The structure is intrinsically sensitive to electrical field, electrical excitation pattern, temperature (and may be amenable to use in a focal plane array), acceleration, shock, distance, etc.   The technology relies on excitation of a mechanical structure at a non-harmonic frequency (i.e. a superharmonic), which can result in increased fractional sensitivity to an influence.  In turn, this increased fractional sensitivity may be interpreted as a high gain, without need for an intervening electronic amplifier.  Another aspect is the availability of switching outputs from MEMS which enables to finely control the switching behavior (either reversible or latching), and thus provide a low impedance, low noise output at high speed without an electronic comparator.  This permits, for example, ultra low cost, low power sensors of various types, which do not require analog electronic components in the output circuit.  Indeed, the technology may be used to modify other MEMS, and therefore the device need not be dedicated.  Thus, for example, the technology might be applied to large arrays, similar to a DLP device, to provide a complex array sensor with reduced output interface complexity, especially as compared to typical MEMS which require an analog output circuit for each MEMS structure. 

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https://commons.wikimedia.org/wiki/File:SparkFun_Triple-Axis-Accelerometer-Breakout_LIS331_10345-01.jpg

 Advantages:  

• Simple and inexpensive to batch-fabricate, calibrate and operate
• Low-power consumption
• Works in changing damping conditions and a range of shock durations
• Can be calibrated to trigger at wide range of accelerations (small and very large)
• Distinctive and strong signal that is not sensitive to noise
• Can add a switching function to an existing MEMS vibrating structure

 Applications:  

• The novel smart switch mechanism can be built into a MEMS device and employed to trigger airbags in vehicles or helmets and other safety gear, and to protect hard drives in portable electronics such as laptops/cell phones upon impact.
• As an accelerometer, the devices can be used in missile and rocket guidance systems, virtual reality headsets, for oil exploration and earthquake monitoring, smart buildings and smart cars, intelligent early-warning and alarm systems, and for smoothing robot movements.

Intellectual Property Summary:

• U.S. 7,493,815 
• U.S. 8,256,291 
• U.S. 9,016,124

Additional Information:  

Inventor Profile